152' WORLD
loess the Hwang-Ho and its tributaries have carved their way, making in the course of time a number of steep-sided ravines. Millions of people live on the floors of these valleys, for the soil is very fertile where there is water* Many of the people live in caves which they have dug out in the steep sides of the valleys, and even where it is known that there are thousands of dwellers it may be almost impossible to find a single house. The loess is a crumbling yellow kind of earth which stains everything that it touches. The soil is yellow, the houses are yellow, the roads are yellow, Hwang-Ho means Yellow River, and the national colour of China is yellow.
As the river comes out of the mountains it bears a heavy load of fine silt, and with this It has built up the Great Plain of China, perhaps the most thickly peopled plain in the world. At its northern end stands Pekin, the capital of China. The city is divided into two oblong towns, one for the people and one for the government, and each is surrounded by high thick walls that were built to keep out robbers. The two towns are again enclosed by a wall and a moat. Pekin is a dirty city and is troubled, from time to time, by the dust-laden winds from the west.
Much of the silt which is brought down by the Hwang-Ho is, every year, deposited on the bed of the river itself, which is thus raised so